1. Field of the Invention
This invention relates to an audio signal encoding apparatus. This invention also relates to an optical recording medium. In addition, this invention relates to an audio signal decoding apparatus. Furthermore, this invention relates to a method of transmitting an audio signal, and a transmission medium.
2. Description of the Related Art
Highly efficient encoding of an audio signal includes a step of compressing the audio signal. Highly efficient encoding techniques are classified into two types; the lossy encoding techniques and the lossless encoding techniques. Among the lossy encoding techniques, the xe2x80x9cacoustic encodingxe2x80x9d is well known as a technique which renders the data deterioration acoustically undetectable. On the other hand, according to the lossless encoding and decoding techniques, the recovered data are exactly the same as the original data.
In general, a sampled or uniformly quantized audio signal has significant redundancy. During the encoding of such an audio signal, the degree of the compression of the audio signal rises as redundancy is more effectively removed therefrom.
It is a first object of this invention to provide an improved audio signal encoding apparatus.
It is a second object of this invention to provide an improved optical recording medium.
It is a third object of this invention to provide an improved audio signal decoding apparatus.
It is a fourth object of this invention to provide an improved method of transmitting an audio signal.
It is a fifth object of this invention to provide an improved transmission medium.
A first aspect of this invention provides an audio signal encoding apparatus comprising means for compressing multiple-channel digital audio signals into compression-resultant multiple-channel signals respectively, the multiple-channel digital audio signals relating to a sampling frequency and a quantization bit number; and means for formatting the compression-resultant multiple-channel signals, a signal representative of the sampling frequency, and a signal representative of the quantization bit number into a formatting-resultant signal, the formatting-resultant signal containing a sub packet and a sync information portion, the sub packet containing at least portions of the compression-resultant multiple-channel signals, the sync information portion containing the signal representative of the sampling frequency and the signal representative of the quantization bit number.
A second aspect of this invention provides an optical recording medium storing a formatting-resultant signal containing a sub packet and a sync information portion, the sub packet containing at least portions of compression-resultant multiple-channel signals which result from compressing multiple-channel digital audio signals respectively, the sync information portion containing a signal representative of a sampling frequency related to the multiple-channel digital audio signals and a signal representative of a quantization bit number related to the multiple-channel digital audio signals.
A third aspect of this invention provides an audio signal decoding apparatus comprising means for separating a formatting-resultant signal into a sub packet and a sync information portion; means for extracting compression-resultant multiple-channel signals from the sub packet; means for expanding the extracted compression-resultant multiple-channel signals into multiple-channel digital audio signals respectively; means for extracting a signal representative of a sampling frequency and a signal representative of a quantization bit number from the sync information portion; and means for converting the multiple-channel digital audio signals into analog audio signals in response to the signal representative of the sampling frequency and the signal representative of the quantization bit number.
A fourth aspect of this invention provides a method of transmitting an audio signal. The method comprises the steps of compressing multiple-channel digital audio signals into compression-resultant multiple-channel signals respectively, the multiple-channel digital audio signals relating to a sampling frequency and a quantization bit number; formatting the compression-resultant multiple-channel signals, a signal representative of the sampling frequency, and a signal representative of the quantization bit number into a formatting-resultant signal, the formatting-resultant signal containing a sub packet and a sync information portion, the sub packet containing at least portions of the compression-resultant multiple-channel signals, the sync information portion containing the signal representative of the sampling frequency and the signal representative of the quantization bit number; and transmitting the formatting-resultant signal through a communication line.
A fifth aspect of this invention provides an audio signal encoding apparatus comprising means for compressing multiple-channel digital audio signals into compression-resultant multiple-channel signals respectively; and means for formatting the compression-resultant multiple-channel signals and an identifier into a formatting-resultant signal, the formatting-resultant signal containing a sub packet and a sync information portion, the sub packet containing at least portions of the compression-resultant multiple-channel signals, the sync information portion containing the identifier, the identifier representing that signals in the sub packet are compression-resultant signals.
A sixth aspect of this invention provides an optical recording medium storing a formatting-resultant signal containing a sub packet and a sync information portion, the sub packet containing at least portions of compression-resultant multiple-channel signals which result from compressing multiple-channel digital audio signals respectively, the sync information portion containing an identifier representing that signals in the sub packet are compression-resultant signals.
A seventh aspect of this invention provides an audio signal decoding apparatus comprising means for separating a formatting-resultant signal into a sub packet and a sync information portion; means for extracting compression-resultant multiple-channel signals from the sub packet; means for extracting an identifier from the sync information portion, the identifier representing that signals in the sub packet are compression-resultant signals; and means for expanding the extracted compression-resultant multiple-channel signals into multiple-channel digital audio signals in response to the extracted identifier, respectively.
An eighth aspect of this invention provides a method of transmitting an audio signal. The method comprises the steps of compressing multiple-channel digital audio signals into compression-resultant multiple-channel signals respectively; formatting the compression-resultant multiple-channel signals and an identifier into a formatting-resultant signal, the formatting-resultant signal containing a sub packet and a sync information portion, the sub packet containing at least portions of the compression-resultant multiple-channel signals, the sync information portion containing the identifier, the identifier representing that signals in the sub packet are compression-resultant signals; and transmitting the formatting-resultant signal through a communication line.
A ninth aspect of this invention provides a DVD-audio disc storing an audio pack loaded with a formatting-resultant signal containing a sub packet and a sync information portion, the sub packet containing at least portions of compression-resultant multiple-channel signals which result from compressing multiple-channel digital audio signals respectively, the sync information portion containing a signal representative of a sampling frequency related to the multiple-channel digital audio signals and a signal representative of a quantization bit number related to the multiple-channel digital audio signals.
A tenth aspect of this invention is based on the third aspect thereof, and provides an audio signal decoding apparatus further comprising means for separating an audio packet from an audio pack, the audio packet containing said formatting-resultant signal.
An eleventh aspect of this invention provides a DVD-audio disc storing an audio pack loaded with a formatting-resultant signal containing a sub packet and a sync information portion, the sub packet containing at least portions of compression-resultant multiple-channel signals which result from compressing multiple-channel digital audio signals respectively, the sync information portion containing an identifier representing that signals in the sub packet are compression-resultant signals.
A twelfth aspect of this invention is based on the seventh aspect thereof, and provides an audio signal decoding apparatus further comprising means for separating an audio packet from an audio pack, the audio packet containing said formatting-resultant signal.
A thirteenth aspect of this invention provides a transmission medium for transmitting data being in a format and being made by a method comprising the steps of compressing multiple-channel digital audio signals into compression-resultant multiple-channel signals respectively; and formatting the compression-resultant multiple-channel signals and an identifier into a formatting-resultant signal, the formatting-resultant signal containing a sub packet and a sync information portion, the sub packet containing at least portions of the compression-resultant multiple-channel signals, the sync information portion containing the identifier, the identifier representing that signals in the sub packet are compression-resultant signals.
A fourteenth aspect of this invention provides a transmission medium for transmitting a formatting-resultant signal containing a sub packet and a sync information portion, the sub packet containing at least portions of compression-resultant multiple-channel signals which result from compressing multiple-channel digital audio signals respectively, the sync information portion containing an identifier representing that signals in the sub packet are compression-resultant signals.
A fifteenth aspect of this invention provides a transmission medium for transmitting a formatting-resultant signal which is decoded by an audio signal decoding apparatus comprising means for separating the formatting-resultant signal into a sub packet and a sync information portion; means for extracting compression-resultant multiple-channel signals from the sub packet; means for extracting an identifier from the sync information portion, the identifier representing that signals in the sub packet are compression-resultant signals; and means for expanding the extracted compression-resultant multiple-channel signals into multiple-channel digital audio signals in response to the extracted identifier, respectively.
A sixteenth aspect of this invention provides a transmission medium for transmitting an audio signal by a method comprising the steps of compressing multiple-channel digital audio signals into compression-resultant multiple-channel signals respectively; formatting the compression-resultant multiple-channel signals and an identifier into a formatting-resultant signal, the formatting-resultant signal containing a sub packet and a sync information portion, the sub packet containing at least portions of the compression-resultant multiple-channel signals, the sync information portion containing the identifier, the identifier representing that signals in the sub packet are compression-resultant signals; and transmitting the formatting-resultant signal through a communication line.
A seventeenth aspect of this invention provides a transmission medium for transmitting data being in a format and being made by an audio signal encoding apparatus comprising means for compressing multiple-channel digital audio signals into compression-resultant multiple-channel signals respectively, the multiple-channel digital audio signals relating to a sampling frequency and a quantization bit number; and means for formatting the compression-resultant multiple-channel signals, a signal representative of the sampling frequency, and a signal representative of the quantization bit number into a formatting-resultant signal, the formatting-resultant signal containing a sub packet and a sync information portion, the sub packet containing at least portions of the compression-resultant multiple-channel signals, the sync information portion containing the signal representative of the sampling frequency and the signal representative of the quantization bit number.
An eighteenth aspect of this invention provides a transmission medium for transmitting a formatting-resultant signal containing a sub packet and a sync information portion, the sub packet containing at least portions of compression-resultant multiple-channel signals which result from compressing multiple-channel digital audio signals respectively, the sync information portion containing a signal representative of a sampling frequency related to the multiple-channel digital audio signals and a signal representative of a quantization bit number related to the multiple-channel digital audio signals.
A nineteenth aspect of this invention provides a transmission medium for transmitting a formatting-resultant signal which is decoded by an audio signal decoding apparatus comprising means for separating a formatting-resultant signal into a sub packet and a sync information portion; means for extracting compression-resultant multiple-channel signals from the sub packet; means for expanding the extracted compression-resultant multiple-channel signals into multiple-channel digital audio signals respectively; means for extracting a signal representative of a sampling frequency and a signal representative of a quantization bit number from the sync information portion; and means for converting the multiple-channel digital audio signals into analog audio signals in response to the signal representative of the sampling frequency and the signal representative of the quantization bit number.
A twentieth aspect of this invention provides a transmission medium for transmitting an audio signal by a method comprising the steps of compressing multiple-channel digital audio signals into compression-resultant multiple-channel signals respectively, the multiple-channel digital audio signals relating to a sampling frequency and a quantization bit number; formatting the compression-resultant multiple-channel signals, a signal representative of the sampling frequency, and a signal representative of the quantization bit number into a formatting-resultant signal, the formatting-resultant signal containing a sub packet and a sync information portion, the sub packet containing at least portions of the compression-resultant multiple-channel signals, the sync information portion containing the signal representative of the sampling frequency and the signal representative of the quantization bit number; and transmitting the formatting-resultant signal through a communication line.
A twenty-first aspect of this invention provides an audio signal encoding apparatus comprising an fs conversion circuit for equalizing sampling frequencies of first multiple-channel digital audio signals to convert a set of the first multiple-channel digital audio signals into a set of second multiple-channel digital audio signals; means for compressing the second multiple-channel digital audio signals into compression-resultant multiple-channel signals respectively, the second multiple-channel digital audio signals relating to a sampling frequency and a quantization bit number; and means for formatting the compression-resultant multiple-channel signals, a signal representative of the sampling frequency, and a signal representative of the quantization bit number into a formatting-resultant signal, the formatting-resultant signal containing a sub packet and a sync information portion, the sub packet containing at least portions of the compression-resultant multiple-channel signals, the sync information portion containing the signal representative of the sampling frequency and the signal representative of the quantization bit number.
A twenty-second aspect of this invention provides an optical recording medium storing a formatting-resultant signal containing a sub packet and a sync information portion, the sub packet containing at least portions of compression-resultant multiple-channel signals which result from equalizing sampling frequencies of multiple-channel digital audio signals and then compressing the multiple-channel digital audio signals respectively, the sync information portion containing a signal representative of a sampling frequency related to the multiple-channel digital audio signals and a signal representative of a quantization bit number related to the multiple-channel digital audio signals.
A twenty-third aspect of this invention provides a method of transmitting an audio signal, comprising the steps of equalizing sampling frequencies of first multiple-channel digital audio signals to convert a set of the first multiple-channel digital audio signals into a set of second multiple-channel digital audio signals; compressing the second multiple-channel digital audio signals into compression-resultant multiple-channel signals respectively, the second multiple-channel digital audio signals relating to a sampling frequency and a quantization bit number; formatting the compression-resultant multiple-channel signals, a signal representative of the sampling frequency, and a signal representative of the quantization bit number into a formatting-resultant signal, the formatting-resultant signal containing a sub packet and a sync information portion, the sub packet containing at least portions of the compression-resultant multiple-channel signals, the sync information portion containing the signal representative of the sampling frequency and the signal representative of the quantization bit number; and transmitting the formatting-resultant signal through a communication line.
A twenty-fourth aspect of this invention provides a transmission medium for transmitting an audio signal by a method comprising the steps of equalizing sampling frequencies of first multiple-channel digital audio signals to convert a set of the first multiple-channel digital audio signals into a set of second multiple-channel digital audio signals; compressing the second multiple-channel digital audio signals into compression-resultant multiple-channel signals respectively, the second multiple-channel digital audio signals relating to a sampling frequency and a quantization bit number; formatting the compression-resultant multiple-channel signals, a signal representative of the sampling frequency, and a signal representative of the quantization bit number into a formatting-resultant signal, the formatting-resultant signal containing a sub packet and a sync information portion, the sub packet containing at least portions of the compression-resultant multiple-channel signals, the sync information portion containing the signal representative of the sampling frequency and the signal representative of the quantization bit number; and transmitting the formatting-resultant signal through a communication line.